When you take an SSRI, a class of antidepressants that increase serotonin levels in the brain. Also known as selective serotonin reuptake inhibitors, these drugs are among the most prescribed for depression and anxiety. But behind their effectiveness lies a quiet, often overlooked risk: hyponatremia, a dangerous drop in blood sodium levels. Also known as low sodium, this condition can cause confusion, seizures, or even coma if ignored. It’s not rare—studies show up to 1 in 10 older adults on SSRIs develop this side effect, especially in the first few weeks of treatment.
SSRIs like sertraline, fluoxetine, and escitalopram can trigger hyponatremia by making your body hold onto too much water. This happens because serotonin affects how your kidneys handle fluid. The more serotonin your brain has, the more your body thinks it needs to keep water, even when it doesn’t. That dilutes the sodium in your blood. Older adults, women, and people on diuretics are at higher risk. You might not feel anything at first, but as sodium drops, you could get nausea, headaches, fatigue, or trouble thinking clearly. These symptoms are easy to blame on stress or aging—but they’re warning signs.
Hyponatremia from SSRIs doesn’t always show up in blood tests right away. That’s why doctors often check sodium levels after starting or increasing the dose. If caught early, stopping the SSRI or lowering the dose can fix it. But if it’s missed, the consequences can be serious. It’s not just about the drug—it’s about how your body reacts to it. Genetics, kidney health, and other medications all play a role. That’s why some people never have an issue, while others need to switch drugs after just one dose.
What you’ll find below are real-world cases and clear explanations about how SSRIs affect sodium, who’s most vulnerable, and what to do if you suspect something’s wrong. You’ll also see how other medications—like diuretics or antiemetics—can make this risk worse. No fluff. Just facts you can use to protect yourself or someone you care about.
SSRIs can cause dangerous low sodium levels, especially in older adults, leading to confusion, falls, and even coma. Learn the risks, who’s most vulnerable, and safer alternatives like mirtazapine.
